Topical skin components

Abstract

The present invention aims to provide a formulation for a topical skin composition containing ascorbic acid derivatives and antiseptic / bactericidal agents that reduces skin irritation. [Solution] A topical skin composition comprising (A) water-soluble ascorbic acid derivatives selected from the group consisting of ascorbic acid and its derivatives, (B) a bactericidal or preservative selected from the group consisting of isopropylmethylphenol and quaternary ammonium salts, and (C) hydrolyzed silk has reduced skin irritation.

Description

Technical Field

[0001] The present invention relates to a low-irritant topical skin composition containing ascorbic acid.

Background Art

[0002] Ascorbic acids are known as so-called whitening components that suppress melanin production and / or dilute the produced melanin, and are formulated and used in topical skin compositions for the purpose of obtaining a skin pigmentation inhibitory effect (Patent Documents 1 to 3).

[0003] Benzalkonium chloride and isopropylmethylphenol, which are bactericides, are among the few substances having both a bactericidal effect and an antiseptic effect, and these are mainly used as antiseptics in cosmetics (Non-Patent Document 1). Methylparaben and propylparaben are also widely used as cosmetic preservatives (Non-Patent Document 2).

[0004] Hydrolyzates of proteins are known to have various functionalities and are formulated and used in topical skin compositions, hair compositions, etc. For example, hydrolyzed elastin contains a large amount of glycine and protects the skin or hair (Non-Patent Document 3). Hydrolyzed collagen contains a large amount of glycine and protects the hair or skin (Non-Patent Document 3). Hydrolyzed royal jelly protein has a high skin irritation-relieving effect (Non-Patent Document 4). Hydrolyzed silk contains a large amount of serine, enhances the moisturizing effect of the hair, forms a film, and protects the cuticle (Non-Patent Document 3).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

[0006] [Non-Patent Document 1] Asaga, Yoshio (2021) "Basic Q&A on Preservation Technology for Various Cosmetics" Q&A 122. Guidebook to Microbial Testing of Cosmetics: Product Edition - From Preservation Design and Manufacturing Process Control to Shipment Inspection and Complaint Handling - , 10-45. [Non-Patent Document 2] T.E. Haag & D.F. Loncrini (1990) "Esters of parahydroxybenzoic acid." The Science of Cosmetics, Pharmaceuticals, Preservatives and Bactericides, 49-62. [Non-Patent Document 3] Beauty Navi, Ingredient Dictionary, [online], December 14, 2020, Delicias AC Co., Ltd. [Searched December 7, 2024], Internet<URL:https: / / vi-navi.com / dictionary-2 / component / #ka> [Non-Patent Document 4] Royal Bio Site, [online], April 1, 2010, Matsumoto Kosho Co., Ltd. [Retrieved December 7, 2024], Internet<URL:https: / / matsumoto-trd.com / wp-content / uploads / 2023 / 07 / e45-5.pdf> [Overview of the project] [Problems that the invention aims to solve]

[0007] When preservatives and bactericides are added to topical skin compositions containing ascorbic acid derivatives, skin irritation is likely to occur upon application. Therefore, this disclosure aims to provide a formulation for topical skin compositions containing ascorbic acid derivatives and preservatives and bactericides that reduces skin irritation. [Means for solving the problem]

[0008] The inventors attempted to reduce skin irritation in a topical skin composition containing ascorbic acid derivatives and preservatives / bactericides by incorporating protein hydrolysates with skin-protective or skin-irritation-reducing properties, but were unable to reduce skin irritation. However, it was unexpectedly discovered that a significant reduction in skin irritation was specifically achieved when a water-soluble compound was selected as the ascorbic acid derivative, isopropylmethylphenol or a quaternary ammonium salt was selected as the preservative / bactericide, and hydrolyzed silk, which has a hair-protective effect, was selected as the protein hydrolysate. This disclosure was completed based on this finding and further investigations.

[0009] In other words, this disclosure provides inventions in the following embodiments. Item 1. A composition for external use on the skin comprising (A) water-soluble ascorbic acids selected from the group consisting of ascorbic acid and its derivatives, (B) a bactericidal or antiseptic agent selected from the group consisting of isopropylmethylphenol and quaternary ammonium salts, and (C) hydrolyzed silk. Item 2. The topical skin composition according to Item 1, wherein component (A) is selected from the group consisting of ascorbic acid, ascorbic acid esters, ascorbyl ethers, ascorbic acid glycosides, and salts thereof. Item 3. The topical skin composition according to item 1 or 2, wherein the (B) component is isopropylmethylphenol and / or benzalkonium chloride. Item 4. A topical skin composition according to any one of items 1 to 3, wherein the content of component (C) per 1 part by weight of component (B) is 0.01 to 100 parts by weight. Item 5. A topical skin composition according to any one of items 1 to 4, wherein the content of component (B) per 100 parts by weight of component (A) is 0.01 to 300 parts by weight. [Effects of the Invention]

[0010] According to this disclosure, a formulation is provided for a topical skin composition containing ascorbic acid derivatives and antiseptic / bactericidal agents that reduces skin irritation. [Modes for carrying out the invention]

[0011] The topical skin composition of this disclosure is characterized by comprising (A) water-soluble ascorbic acid derivatives selected from the group consisting of ascorbic acid and its derivatives (hereinafter also referred to as "component (A)"), (B) a bactericidal or preservative selected from the group consisting of isopropylmethylphenol and quaternary ammonium (hereinafter also referred to as "component (B)"), and (C) hydrolyzed silk (hereinafter also referred to as "component (C)"). The topical skin composition of this disclosure will be described in detail below. In this disclosure, the numerical range "X~Y" refers to a range of X or more and Y or less.

[0012] The topical skin compositions of this disclosure have reduced skin irritation. The topical skin compositions of the preferred embodiments of this disclosure have a less sticky feel. Stickiness refers to poor hand glide over the film of the topical skin composition on the skin immediately after application. The topical skin compositions of the preferred embodiments of this disclosure have reduced skin stickiness. Stickiness refers to the sticky feeling of the skin after the topical skin composition has been absorbed into the skin. The topical skin compositions of the preferred embodiments of this disclosure have excellent skin smoothness. Smoothness refers to a smooth state on the skin surface after the topical skin composition has been absorbed into the skin, where unevenness is not easily felt. The topical skin compositions of the preferred embodiments of this disclosure have excellent skin moisturizing properties. The topical skin compositions of the preferred embodiments of this disclosure have a stable appearance. The topical skin compositions of the preferred embodiments of this disclosure have reduced odor.

[0013] (A) Water-soluble ascorbic acids The topical skin composition disclosed herein contains, as component (A), a water-soluble ascorbic acid derivative selected from the group consisting of ascorbic acid and its derivatives. Ascorbic acid derivatives are known components with whitening and antioxidant effects.

[0014] The ascorbic acid and its derivatives used in this disclosure are, specifically, ascorbic acid, ascorbic acid esters, ascorbyl ethers, ascorbic acid glycosides, and salts thereof.

[0015] The ascorbic acid esters are not particularly limited as long as they are pharmaceutically or cosmetically acceptable. Examples thereof include ascorbic acid phosphate esters (ascorbic acid monophosphate ester, ascorbic acid diphosphate ester, ascorbic acid triphosphate ester), ascorbic acid sulfate esters (ascorbic acid monosulfate ester, ascorbic acid disulfate ester, ascorbic acid trisulfate ester), and the like.

[0016] The ascorbyl ethers are not particularly limited as long as they are pharmaceutically or cosmetically acceptable. Examples thereof include ethyl ascorbic acid (2-O-ethyl ascorbic acid, 3-O-ethyl ascorbic acid), 3-glyceryl ascorbic acid, bisglyceryl ascorbic acid, alkyl glyceryl ascorbic acid, and the like.

[0017] The ascorbic acid glycosides are not particularly limited as long as they are pharmaceutically or cosmetically acceptable. Examples thereof include ascorbic acid glucoside.

[0018] When the ascorbic acids are in the form of acid salts, the types of the salts are not particularly limited as long as they are pharmaceutically or cosmetically acceptable. Examples thereof include sodium salts, potassium salts, magnesium salts, calcium salts, barium salts, ammonium salts, monoethanolamine salts, diethanolamine salts, triethanolamine salts, monoisopropanolamine salts, triisopropanolamine salts, and noil-ascorbic acid.

[0019] These water-soluble ascorbic acids may be either the L-form or the D-form, with the L-form being preferred.

[0020] These components (A) may be used alone or in combination of two or more.

[0021] Among these (A) components, from the viewpoint of suppressing stiffness and / or improving smoothness, preferably are ascorbic acid esters, ascorbyl ethers, ascorbic acid glycosides, and salts thereof (more preferably ascorbic acid phosphate esters, ethyl ascorbic acid, ascorbic acid glucoside, and salts thereof, even more preferably magnesium salts of ascorbic acid phosphate esters, 3-O-ethyl ascorbic acid, and ascorbic acid glucoside; from the viewpoint of improving smoothness, more preferably are ascorbic acid esters or salts thereof, even more preferably ascorbic acid phosphate esters or salts thereof, and even more preferably magnesium salts of ascorbic acid phosphate esters; from the viewpoint of improving moisturizing sensation, preferably are ascorbyl ethers, and more preferably 3-O-ethyl ascorbic acid.

[0022] The content of component (A) in the topical skin composition of this disclosure may be set appropriately depending on the desired degree of action of component (A), for example, 0.01 to 10% by weight. Furthermore, from the viewpoint of suppressing stickiness, suppressing tackiness, and improving smoothness, a preferred content of component (A) is 0.1 to 6% by weight, more preferably 0.5 to 4% by weight or 1 to 4% by weight. Also, from the viewpoint of improving moisturizing sensation, a preferred content of component (A) is 1.5 to 10% by weight, more preferably 2 to 10% by weight.

[0023] (B) Bactericides or preservatives The topical skin composition of this disclosure contains, as component (B), a bactericidal or preservative selected from the group consisting of isopropylmethylphenol and quaternary ammonium salts. Component (B), when incorporated into the topical skin composition containing components (A) and (C), reduces irritation. In a preferred embodiment, component (B), when incorporated into the topical skin composition containing components (A) and (C), suppresses stickiness or stabilizes the appearance.

[0024] The types of quaternary ammonium salts used in this disclosure are not particularly limited, as long as they have bactericidal or antiseptic properties and are pharmaceutically or cosmetically acceptable. Examples include cetylpyridinium chloride, benzethonium chloride, benzalkonium chloride, decalinium chloride, alkyldimethylammonium chloride, alkyltrimethylammonium chloride, methylbenzethonium chloride, and lauroylcholaminoformylmethylpyridinium chloride. These quaternary ammonium salts may be used individually or in combination of two or more.

[0025] Among these components (B), isopropylmethylphenol is preferred from the viewpoint of suppressing stickiness and odor. Furthermore, when a quaternary ammonium salt is used as component (B), among the above quaternary ammonium salts, benzalkonium chloride is preferred from the viewpoint of reducing irritation, suppressing stickiness, or improving appearance stability.

[0026] The content of component (B) in the topical skin composition of this disclosure may be set appropriately according to the desired degree of irritation reduction, stickiness suppression, or appearance stability, but for example, 0.001 to 0.3% by weight is a possible value. From the viewpoint of improving irritation reduction, stickiness suppression, or appearance stability, a preferred value is 0.002 to 0.1% by weight, more preferably 0.003 to 0.05% by weight. Even more preferably, the content of component (B) is 0.005 to 0.05% by weight, more preferably 0.007 to 0.04% by weight, or 0.008 to 0.035% by weight when isopropylmethylphenol is used as component (B); and 0.003 to 0.03% by weight when a quaternary ammonium salt is used as component (B), more preferably 0.004 to 0.01% by weight, or 0.0045 to 0.008% by weight.

[0027] In the topical skin composition of this disclosure, the ratio of component (A) to component (B) is determined according to the content of each component, but from the viewpoint of reducing irritation, suppressing stickiness, or improving appearance stability, preferably the amount of component (B) per 100 parts by weight of component (A) is 0.01 to 300 parts by weight, preferably 0.05 to 200 parts by weight, and more preferably 0.1 to 100 parts by weight. From the viewpoint of suppressing stickiness or improving smoothness, even more preferably the amount is 0.15 to 100 parts by weight, 0.2 to 50 parts by weight, 0.25 to 30 parts by weight, 0.3 to 10 parts by weight, 0.35 to 5 parts by weight, or 0.4 to 3 parts by weight.

[0028] (C) Hydrolyzed Silk The topical skin composition of this disclosure contains hydrolyzed silk as component (C). Component (C), when incorporated into a topical skin composition containing components (A) and (B), reduces irritation. In a preferred embodiment, component (C), when incorporated into a topical skin composition containing components (A) and (B), suppresses stickiness, reduces tackiness, improves smoothness, or improves moisturizing sensation.

[0029] The hydrolyzed silk used in this disclosure is obtained by hydrolyzing silk protein with an acid, alkali, or enzyme. The silk protein may be a mixture of proteins mainly composed of fibroin and sericin, or it may be purified sericin.

[0030] The molecular weight distribution of hydrolyzed silk used in this disclosure is not particularly limited, but examples include 500 to 200,000. From the viewpoint of reducing irritation, suppressing stickiness, suppressing stickiness, smoothness, or moisturizing effect, preferred molecular weight distributions of hydrolyzed silk include 1,000 to 160,000, more preferably 3,000 to 130,000, even more preferably 4,000 to 80,000, and even more preferably 5,300 to 42,000.

[0031] The average molecular weight of hydrolyzed silk used in this disclosure is not particularly limited, but examples include 5,000 to 100,000. From the viewpoint of reducing irritation, suppressing stickiness, suppressing stickiness, smoothness, or moisturizing effect, preferred average molecular weights of hydrolyzed silk include 7,000 to 50,000, more preferably 9,000 to 30,000, even more preferably 10,000 to 20,000, and even more preferably 13,000 to 17,000. In this disclosure, the average molecular weight of hydrolyzed silk refers to the weight-average molecular weight measured by gel permeation chromatography (GPC) using high-performance liquid chromatography.

[0032] The content of component (C) in this disclosure is not particularly limited and can be appropriately set according to the desired degree of irritation reduction, friction suppression, stickiness suppression, smoothness, or moisturizing effect, for example, 0.0001 to 1% by weight is a possible range. From the viewpoint of enhancing irritation reduction, friction suppression, stickiness suppression, smoothness, or moisturizing effect, a preferred range is 0.0003 to 0.8% by weight, more preferably 0.0005 to 0.6% by weight; from the viewpoint of further enhancing friction suppression, stickiness suppression, smoothness, moisturizing effect, or appearance stability, even more preferably 0.02 to 0.2% by weight, 0.025 to 0.1% by weight, 0.03 to 0.08% by weight, 0.04 to 0.08% by weight, or 0.05 to 0.08% by weight is a possible range.

[0033] In the topical skin composition of this disclosure, the ratio of component (A) to component (C) is determined according to the content of each component, but from the viewpoint of reducing irritation, suppressing stickiness, suppressing greasiness, smoothness, or moisturizing effect, preferably the amount of component (C) per 100 parts by weight of component (A) is 0.005 to 500 parts by weight. From the viewpoint of reducing irritation, suppressing stickiness, suppressing greasiness, smoothness, or moisturizing effect, preferably 0.015 to 400 parts by weight, more preferably 0.025 to 300 parts by weight; and from the viewpoint of further enhancing stickiness, suppressing greasiness, smoothness, moisturizing effect, or appearance stability, even more preferably 1 to 100 parts by weight, 1.25 to 30 parts by weight, 1.5 to 10 parts by weight, 1.75 to 5 parts by weight, 2 to 4 parts by weight, 2.25 to 4 parts by weight, or 2.5 to 4 parts by weight.

[0034] In the topical skin composition of this disclosure, the ratio of component (B) to component (C) is determined according to the content of each component, but from the viewpoint of reducing irritation, suppressing stickiness, suppressing stickiness, smoothness, or moisturizing effect, preferably the amount of component (C) per 1 part by weight of component (B) is 0.01 to 100 parts by weight, more preferably 0.03 to 80 parts by weight, and even more preferably 0.05 to 60 parts by weight; from the viewpoint of further enhancing the suppression of stickiness, suppressing stickiness, smoothness, moisturizing effect, or appearance stability, even more preferably the amount is 0.1 to 40 parts by weight, 0.5 to 30 parts by weight, 0.75 to 20 parts by weight, 2 to 10 parts by weight, or 4.5 to 8 parts by weight.

[0035] (D) Ethanol In preferred embodiments, the topical skin compositions of this disclosure contain ethanol as component (D). More specifically, if component (B) contains isopropylmethylphenol, it is preferable to further contain component (D).

[0036] If the topical skin composition of this disclosure contains component (D), the content of component (D) is not particularly limited, but examples include 0.5 to 15% by weight, preferably 0.8 to 12% by weight, 0.8 to 5% by weight, 0.8 to 3% by weight, 0.8 to 1.5% by weight, 2 to 12% by weight, 4 to 12% by weight, 6 to 12% by weight, or 8 to 12% by weight.

[0037] When the topical skin composition of this disclosure contains isopropylmethylphenol and component (D) as component (B), the ratio of isopropylmethylphenol to component (D) is determined according to the content of each of the above components, but preferably the content of component (D) per 1 part by weight of isopropylmethylphenol is 30 to 500 parts by weight, preferably 60 to 400 parts by weight, more preferably 90 to 350 parts by weight, 100 to 250 parts by weight, 150 to 150 parts by weight, 200 to 350 parts by weight, 230 to 350 parts by weight, or 250 to 350 parts by weight.

[0038] Other ingredients The topical skin compositions of this disclosure may or may not contain, in addition to the components described above, pharmaceutically or cosmetically acceptable bases and / or additives as needed. Examples of such bases and additives, whether present or absent, include water, surfactants, polyhydric alcohols, chelating agents, pH adjusters, buffers, preservatives, antioxidants, stabilizers, fragrances, colorants, etc. When these bases and / or additives are included in the topical skin compositions of this disclosure, their content may be appropriately determined depending on the type of base and / or additive used.

[0039] Examples of polyhydric alcohols in the topical skin compositions of this disclosure include ethylene glycol, butylene glycol, polyethylene glycol, and glycerin.

[0040] If the topical skin composition of this disclosure contains a pH adjuster, examples of pH adjusters include phosphoric acid, hydrochloric acid, citric acid, sodium citrate, succinic acid, tartaric acid, sodium hydroxide, potassium hydroxide, triethanolamine, triisopropanolamine, and the like. Among these pH adjusters, citric acid, sodium citrate, and potassium hydroxide are preferred.

[0041] Furthermore, the topical skin compositions of this disclosure may also contain pharmacological components in addition to the components described above. Examples of such pharmacological components include antihistamines, local anesthetics, moisturizers, anti-inflammatory agents, bactericides, antipruritics, skin protectants, blood circulation promoting components, vitamins, and the like. These pharmacological components may be used individually or in combination of two or more. When these pharmacological components are included in the topical skin compositions of this disclosure, their concentrations may be appropriately set according to the type of pharmacological component used, the expected effect, etc.

[0042] Dosage form / form The dosage form of the topical skin composition disclosed herein is not particularly limited as long as it is applicable to the skin, and may be liquid, solid, or semi-solid (cream, gel, ointment, paste, etc.). Furthermore, the topical skin composition of the present invention may be a non-emulsified formulation such as an aqueous formulation or an oily formulation, or an emulsified formulation such as an oil-in-water emulsion or a water-in-oil emulsion. Among these dosage forms, aqueous formulations are preferred.

[0043] The formulation of the topical skin composition disclosed herein is not particularly limited as long as it is applicable to the skin, but may be any formulation such as a topical drug, cosmetic, or skin cleanser. Among these formulations, topical drugs and cosmetics are preferred, and cosmetics are more preferred. Furthermore, the cosmetic may be either a leave-on cosmetic or a leave-off cosmetic, but a leave-on cosmetic is preferred.

[0044] More specific formulations of the aforementioned topical skin composition include topical skin medicinal products such as liquids (including lotions, sprays, aerosols, emulsions, and oils), water-soluble ointments, oily ointments, creams, foams, gels, and patches; cosmetics such as ointments, creams, emulsions, lotions, beauty oils, packs, and gels; and skin cleansing products such as body shampoos, hair shampoos, and conditioners. Among these formulations, liquids (more preferably lotions) and lotions are preferred. These formulations can be prepared by compounding them using bases and / or additives appropriate to the formulation, in accordance with known methods described in the General Provisions for Formulations of the Sixteenth Revised Japanese Pharmacopoeia, etc.

[0045] pH The pH of the topical skin composition of this disclosure can be selected without particular limitation from the pH range generally applied to topical skin compositions, for example, 5.5 to 7.5. In this disclosure, the pH of the oral composition is a value measured at a temperature of 25°C. [Examples]

[0046] The present disclosure will be explained in more detail below with reference to examples, but the present disclosure is not limited to these examples.

[0047] Test example The skin-applied compositions (lotions) shown in Tables 1-4 were prepared. The average molecular weight of hydrolyzed silk, as shown in the table, was 15,000, with a molecular weight distribution of approximately 5,500-40,000. The average molecular weight of hydrolyzed collagen was 400, the molecular weight distribution of hydrolyzed elastin was approximately 2,000-5,000, and the average molecular weight of hydrolyzed royal jelly protein was 10,000 or less.

[0048] Eight expert cosmetic evaluation panelists applied appropriate amounts of the prepared topical skin compositions to their faces and scored each of the following evaluation items based on the criteria below: irritation reduction, stickiness suppression, stickiness suppression, smoothness, and moisturizing effect. Furthermore, the same eight panelists scored each of the following evaluation items based on the criteria below: stability (appearance) and stability (odor) after sealing the prepared topical skin compositions in clear glass bottles and leaving them undisturbed at 25°C for 24 hours. The results are shown in Tables 1-4.

[0049] <Irritation reduction> In the following, irritation refers to a tingling or redness of the skin. 4 points: No irritation at all. 3 points: The irritation is barely noticeable. 2 points: I'm concerned about the irritation. 1 point: It's very irritating.

[0050] <Suppression of squeaking> In the following, "stickiness" refers to poor hand glide over the skin surface immediately after application of the topical skin composition (the state in which the topical skin composition is not completely dry on the skin immediately after application). 4 points: No creaking sensation. 3 points: A slight creaking sensation can be felt. 2 points: I feel a creaking sound. 1 point: I feel a very strong creaking sound.

[0051] <Sticky properties> In the following, "stickiness" refers to the state in which the skin feels sticky after the topical skin composition has been applied to the skin (specifically, 2 minutes after application). 4 points: No stickiness. 3 points: Slightly sticky feeling. 2 points: Feels sticky 1 point: I feel a very strong stickiness.

[0052] <Smoothness> In the following, "smoothness" refers to a state in which the skin surface is smooth and does not feel rough after the topical skin composition has been applied to the skin (specifically, 2 minutes after application). 4 points: My skin feels incredibly smooth. 3 points: I can feel the smoothness of my skin. 2 points: I feel a slight smoothness to the skin. 1 point: I don't feel any smoothness in my skin.

[0053] <Moisturizing effect> 4 points: Very moisturizing. 3 points: Moisturizing 2 points: Slightly moisturizing. 1 point: Does not feel moisturizing.

[0054] <Stability (Appearance)> 4 points: colorless and transparent 3 points: Slightly cloudy, but nearly transparent. 2 points: Cloudiness is visible. 1 point: Separation and precipitation are observed.

[0055] <Stability (odor)> 4 points: No noticeable odor at all. 3 points: The smell is barely noticeable. 2 points: The smell is bothersome. 1 point: The smell is very noticeable.

[0056] Based on the total score obtained, each evaluation item was judged according to the following criteria. ◎: 25 points or more ○: 20 points or more, less than 25 points △: 15 points or more but less than 20 points ×: Less than 15 points

[0057] [Table 1]

[0058] [Table 2]

[0059] [Table 3]

[0060] [Table 4]

[0061] As shown in Comparative Examples 1 and 2, topical skin compositions containing components (A) and (B) were prone to causing irritation, and as shown in Comparative Examples 3 to 5, the irritation could not be reduced even when a protein hydrolysate with skin-protective or skin-irritation-reducing properties was further added. In contrast, as shown in Examples 1 to 12, by adding component (C), which is hydrolyzed silk, to a topical skin composition containing components (A) and (B), the irritation was significantly reduced.

[0062] Furthermore, as shown in Comparative Example 6, the topical skin composition containing components (A) and (C) was prone to causing irritation, and as shown in Comparative Examples 7 and 8, the addition of preservatives naturally resulted in continued irritation. In contrast, as shown in Examples 1 to 12, the addition of component (B), which is isopropylmethylphenol or a quaternary ammonium salt, to the topical skin composition containing components (A) and (C) significantly reduced irritation. However, as shown in Comparative Example 9, the combination of components (B) and (C) did not inherently reduce irritation.

[0063] Furthermore, as shown in Comparative Example 10, the topical skin composition containing an oil-soluble vitamin derivative and components (B) and (C) was prone to causing irritation. In contrast, as shown in Examples 1 to 12, the topical skin composition containing water-soluble vitamins components (A), (B), and (C) significantly reduced irritation.

[0064] Thus, it was found that the excellent irritation reduction observed in the topical skin compositions of Examples 1 to 12 is due to the unique effect of selecting water-soluble component (A) as an ascorbic acid, selecting component (B) which is isopropylmethylphenol or a quaternary ammonium as a preservative and bactericide, and selecting component (C) which is hydrolyzed silk as a hydrolyzed protein.

[0065] Furthermore, the topical skin compositions of Examples 1 to 12, through the combination of components (A) to (C), demonstrated overall superiority not only in reducing irritation but also in suppressing stickiness, reducing tackiness, smoothness, moisturizing properties, stability (appearance), and stability (odor).

[0066] Prescription examples Topical skin compositions (lotions) were prepared according to the formulations shown in Tables 5 and 6. The pH was adjusted to 6-7. All of the topical skin compositions were excellent in all aspects, including not only irritation reduction but also anti-stickiness, anti-greasy properties, smoothness, moisturizing properties, stability (appearance), and stability (odor).

[0067] [Table 5]

[0068] [Table 6]

Claims

1. A composition for external use on the skin comprising (A) water-soluble ascorbic acid derivatives selected from the group consisting of ascorbic acid and its derivatives, (B) a bactericidal or antiseptic agent selected from the group consisting of isopropylmethylphenol and quaternary ammonium salts, and (C) hydrolyzed silk.

2. The topical skin composition according to claim 1, wherein component (A) is selected from the group consisting of ascorbic acid, ascorbic acid esters, ascorbyl ethers, ascorbic acid glycosides, and salts thereof.

3. The topical skin composition according to claim 1 or 2, wherein component (B) is isopropylmethylphenol and / or benzalkonium chloride.

4. The topical skin composition according to claim 1 or 2, wherein the content of component (C) per 1 part by weight of component (B) is 0.01 to 100 parts by weight.

5. The topical skin composition according to claim 1 or 2, wherein the content of component (B) per 100 parts by weight of component (A) is 0.01 to 300 parts by weight.

Images